Battery life of a device is a key factor for customers, e.g., when they are deciding on which device to purchase. Additionally, a roaming footprint of the device plays another part in a potential customer's choice, e.g., if the customer is a global traveler. The battery life of a device is affected by various factors, such as (i) a radio access network (RAN) setting of a visited carrier, (ii) device configuration, and/or (iii) data stored within a subscriber identity module (SIM) card of the device. As an example, the data stored within the SIM card can dictate for which carriers to search and/or their priorities.
Standards defined by the 3rd Generation Partnership Project (3GPP) state that, when a device is roaming, the device shall periodically perform public land mobile network (PLMN) searches for higher priority PLMNs belonging to the same serving country. When in automatic mode, search parameters are defined by a preferred PLMN list stored on a SIM (or universal SIM (USIM)) application, for example, universal integrated circuit card (UICC). In most cellular network deployments, a carrier typically uses a single PLMN identifier (ID) nationwide; however, in some cases, a carrier can utilize multiple PLMN IDs for different areas within the country. India is an example of the latter. In the case of India, each carrier offers service in a number of different states (called “Circles”) but the PLMN ID for the same carrier in different circles is different for the different circles, i.e., the different circles do not use a single PLMN ID. In such a scenario, periodic rescans for higher priority PLMNs that may not exist in a particular area, result in a poor user experience and degraded battery life.